Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Sources of Pharmaceuticals in Water

This chapter focuses on the increasing environmental apprehensions and persistence of numerous organic contaminants so-called emerging contaminants (ECs), including biologically active elements from pharmaceutical source industries. Several types of diverse pharmaceutical-related compounds are being detected in environmental matrices and wastewater treatment units. Owing to this broader occurrence, transformation, and detection of pharmaceutical-related compounds in water matrices, people and legislative authorities are now more concerned about potential sources and ecological consequences of ECs. This is mainly because the free movement of ECs in water matrices is posing noteworthy adverse effects on human, aquatic animals, and naturally occurring plants, even at minimal concentrations. So far, several detection and treatment processes have been proposed and exploited against numerous pharmaceutical-related ECs. The useful and side effects of pharmaceutical-related compounds have been extensively inspected. Owing to this substantial research gap, the sources and environmental persistence of pharmaceutical-related ECs and their direct/indirect adverse effects have now been the topic of intensive studies. From the surface water perspective, wastewater treatment plants (WWTPs) are the major source of pharmaceutical-related ECs. The current chapter spotlights the widespread occurrence, numerous sources, and transportation fate of pharmaceutical-related ECs in water matrices.The work is a part of the project entitled “Contaminantes emergentes y priori-tarios en las aguas reutilizadas en agricultura: riesgos y efectos en suelos, produc-ción agrícola y entorno ambiental” funded by CSIC-Tecnologico de Monterrey under iLink program. All listed authors are also grateful to their representative universities/institutes for providing literature facilities.Peer reviewe